Fan and cooling device

ABSTRACT

A cooling device having a first fan, a second fan upstream of the first fan, and a flow conditioner element that includes a housing with a first side having a flow-conditioner plate, a second side opposite the first side that defines an opening, and a duct between the first side and the second side, wherein the flow-conditioner plate is attached to a side of the first fan proximal to the second fan and the second side of the housing is attached to a side of the second fan proximal to the first fan. A method for cooling electronic components and a fan assembly are also disclosed.

BACKGROUND

When in operation, electronic components generate heat which must bedissipated in order to ensure their continued operation and to preventthe build up of heat within the device or cabinet in which theelectronic components are located. This is particularly true withrespect to computer components used in desktops or servers where theincreasing density of components has resulted in increased coolingdemands.

The increased cooling demands can be met by supplying higher airflowthrough the device or system in which the components are located. Due tospace limitations in various devices, including desktops and servers,the installation of larger or parallel fans is not practicable. Onealternative to the use of parallel fans is to use series stacked fans toprovide for higher rates of airflow. Unfortunately, the performance ofthe stacked series fans is reduced due to the non-ideal i.e.,non-uniform entrance flow of air entering the downstream fan.

Various attempts have been made to improve the flow of air entering thedownstream fan. These include the use of outlet guide vanes attached tothe upstream fan in an attempt to provide uniform airflow to thedownstream fan. Additionally, an air gap has been provided between theupstream and downstream fans in an attempt to provide uniform airflow.

Given the need to provide a greater amount of cooling for moreconcentrated electronic components, a device that could generate alarger amount of cooling air at a reduced noise level would be animportant improvement in the art.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a sectional view of a cooling device showing a first andsecond fan and a flow conditioner.

FIG. 2 is a side view of a flow conditioner.

FIG. 3 is a perspective view of a flow conditioner.

FIG. 3A is a perspective view of a flow-conditioner plate.

FIG. 4 is a graph showing the increase in air flow for a given staticpressure.

FIG. 5 is a front view of a flow-conditioner plate.

FIG. 5A is a perspective view of the flow-conditioner plate shown inFIG. 5.

FIG. 6 is a graph showing the increased air flow at a given staticpressure using a flow-conditioner plate as shown in FIG. 5.

FIG. 7 is a table showing the decrease in noise level using the flowconditioner.

FIG. 8 is a graph showing the decrease in noise level at variousfrequencies using the flow conditioner.

FIG. 9 is a side view of a fan assembly.

FIG. 10 is a table showing the increase in flow rate at a given staticpressure for an embodiment of the fan assembly.

FIG. 11 is a perspective view of an embodiment of a fan inlet duet.

FIG. 11A is a perspective view showing the fan connection plate of thefan inlet duct shown in FIG. 11.

FIG. 12 is a perspective view of an embodiment of a fan outlet duct.

FIG. 12A is a perspective view showing the fan connection plate of thefan outlet duct shown in FIG. 12.

DETAILED DESCRIPTION OF THE EMBODIMENTS

The apparatus involves a cooling device 10 for use with electroniccomponents (not shown), in particular, computer components withindesktops, blade enclosures, and servers. As shown in FIG. 1, the coolingdevice 10 comprises a first fan 12, a second fan 14 upstream of thefirst fan 12, and a flow conditioner element 16 that comprises a housing18 having a first side 20 that includes a flow-conditioner plate 22, asecond side 24 opposite the first side 20 that defines an opening 26,and duct 28 between the first side 20 and the second side 24, whereinthe flow-conditioner plate 22 is attached to a side of the first fan 12proximal to the second fan 14 and the second side 24 of the housing 18is attached to a side of the second fan 14 proximal to the first fan 12.

In an embodiment, the first 12 and second 14 fans are axial fans.

In an embodiment, the flow-conditioner plate 22 has a thickness “t”, asshown in FIG. 2, of approximately 4 mm. This flow-conditioner plate 22may be a perforated plate, as is shown in FIG. 3A. Such a plate definesa plurality of openings 30, each one of which may be circular with adiameter of approximately 5 mm, in a particular embodiment. In anembodiment, the flow-conditioner plate 22 may have a circular gratingthat is divided into multiple sections as is shown in FIGS. 5 and 5A.

In still another embodiment, the length and width of the side of thefirst fan 12 proximal to the second fan 14 is equal to the length andwidth of the flow-conditioner plate 22. The duct 28, defined by thehousing 18 between the flow-conditioner plate 22 and the second side 24,may be an elongated duct 28 having a length “L” of at least 13 mm, asshown in FIG. 2. The duct 28 provides for an air gap that exists betweenthe flow-conditioner plate 22 and the second fan 14, as shown in FIGS.1, 2, and 3.

The flow conditioner element 16 may be manufactured of plastic or anylike material.

When in operation, the flow conditioner 16 is aligned axially betweenthe first and second fan 12, 14, downstream of the second fan 14, asshown in FIG. 1. Air flow “A” exits the second fan 14 and proceedsthrough the opening 26 in the second end 24 of the flow conditionerhousing 18, through the air duct 28 to the flow-conditioner plate 22 onthe first end 20 of the housing 18 adjacent to the first fan 12. The air“A” is then drawn through the flow-conditioner plate 22 into the firstfan 12.

In an embodiment, the cooling device 10 is used to cool computercomponents (not shown) that may be located in a desktop computer or aserver. The flow conditioner 16 improves the flow of air entering thedownstream or first fan 12 by generating a more uniform flow of air. Ascan be seen in FIG. 4, using the flow conditioner results in a higherflow rate in cubic feet per minute (“CFM”) being generated by a fan at agiven static pressure. This results in an increase in the airflowthrough the electronic components resulting in greater cooling while thespacing of the fans 12, 14 reduce the noise associated with the airflowthrough the fans 12, 14. This increase in air flow allows for anincrease of the density of components in a given compartment as greatercooling is achieved at a given static pressure than without the use ofthe flow conditioner 16. Likewise, the flow conditioner 16 results in anincrease in energy savings and noise reduction as it allows for aparticular static pressure to be achieved using a lower CFM, and thus alower fan RPM, than a cooling system utilizing cooling fans arranged isseries without a flow conditioner 16.

FIGS. 5 and 5A show another embodiment of the flow-conditioner plate 22used with the cooling device 10. FIG. 6 is a graph showing the increasein flow rate for a given static pressure that result from the use of aflow conditioner 16 with the flow-conditioner plate 22 shown in FIG. 5.

As shown in FIGS. 7 and 8, at low operating frequencies, the greater theair gap between the two fans 12, 14, the lower the noise level. Athigher frequencies, an air gap of at least 13 mm results in a moreeffective level of noise reduction.

Also disclosed is a method of cooling electronic components within anenclosure, the method comprises: (1) generating an air flow from asecond fan 14; (2) drawing the air flow from the second fan 14 throughan opening 26 in a housing 18 positioned downstream of the second fan14; (3) pulling the air flow through a flow-conditioner plate 22 on aside of the housing 18 distal to the second fan 14 into a first fan 12attached to the flow-conditioner panel 22; and (4) generating the airflow downstream from the first fan 12.

In an embodiment, the flow-conditioner plate is a perforated plate.

A fan assembly 32 for cooling electronic components is also disclosed.In an embodiment, as shown in FIG. 9, the fan assembly 32 comprises afan 34; an inlet duct 36 having a first end 38 upstream of the fan 34,said first end 38, as shown in FIGS. 11 and 11A, defines a first opening40 having a first diameter d₁ and a second end 42 downstream of thefirst end 38, said second end 42 attached to a first side 44 of the fan34 and defining a second opening 46 having a second diameter d₂ that issmaller than the first diameter d₁. An outlet duct 48, as shown in FIGS.12 and 12A, has a first end 50 attached to a second side 52 of the fan34 opposite the first side 42, said first end 50 of the outlet duct 48defining an opening 54 having a first diameter d₃; and a second end 56downstream of the first end 50, said second end 56 defining a secondopening 58 having a second diameter d₄ that is greater than the firstdiameter d₄.

The inlet duct 36, as shown in FIG. 11, used in the assembly 32 createsa nozzle effect that allows for a smoother flow of air into the fan 34.The outlet duct 48, as shown in FIG. 12, acts as a diffuser expandingthe air flow out of the fan 34. As shown in FIG. 10, the use of theinlet and outlet duct 36, 48 allows for a greater flow of air at a givenstatic pressure, as shown in FIG. 10, thereby increasing the coolingeffect of the fan 34.

In an embodiment, the diameter d₁ of the first end 38 of the inlet duct36 is equal to the diameter d₄ of the second end 56 of the outlet duct48, and the diameter d₂ of the second end 42 of the inlet duct 36 isequal to the diameter d₃ of the first end 50 of the outlet duct 48.

In still another embodiment, the second end of the outlet duct 56 isattached to a flow conditioner element 16.

The use of the terms “a” and “an” and “the” and similar referents in thecontext of describing the claimed apparatus, device, system, or method(especially in the context of the following claims) are to be construedto cover both the singular and the plural, unless otherwise indicatedherein or clearly contradicted by context. Recitation of ranges ofvalues herein are merely intended to serve as a shorthand method ofreferring individually to each separate value falling within the range,unless otherwise indicated herein, and each separate value isincorporated into the specification as if it were individually recitedherein. All methods described herein can be performed in any suitableorder unless otherwise indicated herein or otherwise clearlycontradicted by context. The use of any and all examples, or exemplarylanguage (e.g., “such as”) provided herein, is intended merely to betterilluminate the claimed apparatus, device, system, or method and does notimpose a scope limitation unless otherwise claimed. No language in thespecification should be construed as indicating any non-claimed elementas essential to the practice of the claimed apparatus, device, system,or method.

Preferred embodiments of the claimed apparatus, device, system, ormethod are described herein, including the best mode known to theinventors for practicing the claimed apparatus, device, system, ormethod. It should be understood that the illustrated embodiments areexemplary only, and should not be taken as limiting the scope of theclaimed apparatus, device, system, or method.

1. A cooling device comprising: a first fan; a second fan upstream ofthe first fan; and a flow conditioner element located between the firstand second fans, the flow conditioner element comprising: a housinghaving a first side that includes a flow-conditioning plate; a secondside opposite the first side that defines an opening; and a duct betweenthe first side and the second side, wherein the flow-conditioning plateis attached to a side of the first fan proximal to the second fan andthe second side of the housing is attached to a side of the second fanproximal to the first fan.
 2. The cooling device of claim 1, wherein thefirst and second fans are axial fans.
 3. The cooling device of claim 1,wherein the flow-conditioning plate has a thickness of approximately 4mm.
 4. The cooling device of claim 3, wherein the flow-conditioningplate is a perforated plate.
 5. The cooling device of claim 4, whereinthe perforated plate has a plurality of circular openings, each having adiameter of approximately 5 mm.
 6. The cooling device of claim 1,wherein: the side of the first fan proximal to the second fan has alength and a width; and the flow-conditioning plate has a length that isequal to the length of the side of the first fan and a width that isequal to the width of said side.
 7. The cooling device of claim 1,wherein the duct between the flow-conditioning plate and the second sideis an elongated duct having a length of at least 13 mm.
 8. The coolingdevice of claim 1, wherein the flow conditioner is manufactured from arigid plastic or like material.
 9. The cooling device of claim 1,wherein an air gap exists between the flow-conditioning plate and thesecond fan.
 10. A method of cooling electronic components within anenclosure, the method comprising: generating an air flow from a secondfan; drawing the air flow from the second fan through an opening in ahousing positioned downstream of the second fan; pulling the air flowthrough a flow-conditioner plate on a side of the housing distal to thesecond fan into a first fan attached to the flow-conditioner plate; andgenerating the air flow downstream from the first fan.
 11. The method ofclaim 10, comprising providing the flow-conditioner plate with aplurality of perforations.
 12. The method of claim 10, comprisinglocating the flow-conditioner plate adjacent the first fan.
 13. Themethod of claim 10, comprising providing the flow-conditioner platehaving a thickness of approximately 4 mm.
 14. A fan assembly for coolingelectronic components, the fan assembly comprising: a fan; an inlet ducthaving: a first end upstream of the fan, said first end defining a firstopening having a first diameter; and a second end downstream of thefirst end, said second end attached to a first side of the fan anddefining a second opening having a second diameter that is smaller thanthe first diameter; an outlet duct having: a first end attached to asecond side of the fan opposite the first side, said first end of theoutlet duct defining an opening having a first diameter, and a secondend downstream of the first end, said second end defining a secondopening having a second diameter that is greater than the firstdiameter.
 15. The fan assembly of claim 14, wherein: the diameter of thefirst end of the inlet duct is equal to the diameter of the second endof the outlet duct; and the diameter of the second end of the inlet ductis equal to the diameter of the first end of the outlet duct.
 16. Thefan assembly of claim 14, wherein the second end of the outlet duct isattached to a flow conditioner element, the flow conditioner elementcomprising: a housing having a first side that includes aflow-conditioning plate; a second side opposite the first side thatdefines an opening; and a duct between the first side and the secondside, wherein the flow-conditioning plate is attached to a side of thefirst fan proximal to the second fan and the second side of the housingis attached to a side of the second fan proximal to the first fan. 17.The fan assembly of claim 14 wherein the fan is an axial fan.